Clumping animal litters are those litters which are initially provided in the form of discrete plural particles, which particles tend to agglomerate into solid masses or clumps when wetted by a liquid such as animal urine. A number of such clumping litters have been provided in the prior art. One advantage of such clumping litters is that the solid clumps formed upon wetting of the litter can be separately removed as discrete entities from the remaining litter and can be discarded by the animal owner, leaving behind a quantity of relatively uncontaminated litter. Animal owners, and in particular owners of animals such as house cats, often find the clumping property of such litters to be convenient for periodic cleaning of the animal litterbox. Some known animal litters have good ammonia-masking properties. Because ammonia is a breakdown product of the urea found in animal urine, the ability of an animal litter to mask the odor of ammonia is a desired property.
Many clumping animal litters are made from clays and other mineral substrates. Such litters typically include particles of a mineral substrate, which substrate functions as an absorbent and/or odor reducer. The particles may be coated with a liquid-activated adhesive material, such as gelatinized starch, on the surfaces of the particles. When wetted, the adhesive material is activated and causes the discrete litter particles to agglomerate into clumps.
Although clay-based litters may be functional as clumping animal litters, such litters suffer from certain drawbacks. For example, one disadvantage of clay litters is the high density of the clay component of the litter. Because of this high density, a heavy mass of litter must be used for a given volume of urine. The resulting clumps of spent litter are somewhat heavy, and thus can fracture in the absence of strong interparticle adhesion. Another disadvantage of clay litters is that, because the clay is not biodegradable, the litter cannot be flushed into some sewerage systems after use. This may be inconvenient for certain animal owners.
In recognition of these drawbacks, the prior art also has provided animal litters made from biodegradable materials, such as seed hulls or other grain-based materials. Such litters are often suitable for disposal by flushing into sewerage systems. In recognition of the advantages inherent in clumping animal litters, the prior art has provided biodegradable litters that exhibit a clumping property. Like typical clumping clay litters, such litters often comprise discrete particles of a liquid-absorbent substrate having a liquid-activated adhesive coated thereon.
Conventional grain-based litters also suffer from a number of drawbacks. For example, spent clumps of such grain-based litters typically are less durable than clumps of clay-based litters. Moreover, conventional grain-based litters also often have a strong odor, which some people find objectionable, and which further may entice animals such as dogs to eat the litter. Moreover, while grain-based clumping litters may initially form cohesive clumps, the long-term cohesiveness of the formed clumps may be poor. Thus, while a solid clump may be formed and remain solid for a short period of time, the clump may tend to disintegrate with time or on handling, making it difficult to separate the spent clumped litter from the litterbox.
Another problem with both clay-based and grain-based clumping litters relates to clumping efficiency, or the amount of litter required to form a clump. Large amounts of conventional litters are required to form a clump, and thus conventional clumping litters are used up quickly. The animal owner thus is forced to replenish the supply of litter frequently.
In light of the drawbacks inherent in known clay-based and grain-based animal litters, there exists a need in the art for a more satisfactory biodegradable clumpable cat litter. Ideally, the litter should be made from a renewable, biodegradable resource, such as a grain-based substrate. The litter should not be edibly attractive to animals, should have a low odor, and should have excellent ammonia masking properties. The litter also should possess acceptable clumping properties, both with respect to initial and long-term cohesiveness of the clumps. It is a general object of the present invention to provide an animal litter that overcomes the drawbacks inherent in known clumping animal litters.